00:01
So in this question we want to prove that if m squared is equal to m squared if and only if n is equal to m or n is equal to minus n.
00:09
So since this is an if and only if we have to prove both directions.
00:14
So first we'll prove this direction.
00:16
So let m squared is equal to n squared, moving everything to one slide is equal to zero.
00:25
Factorizing we have m plus by n times by m minus by n is equal to to 0.
00:33
So since this is equal to 0, either the first product is equal to 0 or the second product is equal to 0.
00:39
So m plus by n is equal to 0 or m minus by n is equal to 0.
00:46
So therefore we have m is equal to minus n, this one, or m is equal to n, which is the second one.
00:56
Now to prove the reverse direction, we want to let m is equal to n or m is equal to minus n...